Ideal Hfc Plant Configuration Issues; Cable Modem Cannot Successfully Range - Juniper G10 CMTS Hardware Manual

Ideal HFC Plant Configuration Issues

• Ideal HFC Plant Configuration Issues
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Cable Modem Cannot Successfully Range

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150 JUNOSg 3.0 G10 CMTS Hardware Guide
This section provides a list of potential HFC plant issues and the procedures to resolve them.
The troubleshooting procedures in this section assume that the HFC plant is ideal and not
contributing to issues associated with the cable modems.
"HFC Plant Related Issues" on page 156 addresses issues associated with problems in the
HFC plant.
This section includes the following topics:
! Cable Modem Cannot Successfully Range on page 150
! Cable Modem Cannot Establish IP Connectivity on page 151
! Cable Modem Cannot Successfully Register on page 151
! Cable Modem Throughput is Slow on page 152
! Cable Modem is Dropped on page 156
If a cable modem cannot successfully range, the cause might be one or more of the following:
! The downstream and upstream interface and port mapping are not properly aligned
with the forward and return path topology of the HFC plant. For example, suppose a
cable modem resides in cable interface 0 (MAC domain 0), which contains downstream
interface 0 and upstream interfaces 0 and 1. Also, suppose the forward and return paths
are connected to downstream port 0 and upstream port 0 of an HFC Connector Module
or SIM. If you manually reconfigured the CMTS so that upstream interface 0 is moved to
upstream port 1, but the interface still resides in cable interface 0, when upstream
interface 0 is enabled, the CMTS will be expecting the cable modem to transmit on
port 1, but the cable modem will be transmitting its ranging requests on port 0.
! The upstream interface on which the cable modem resides is not enabled.
A high IM value in the flap list can be an indication of ranging issues.
The local event log might contain events that explain why a cable modem has been
de-ranged. Issue the show log cable command to see the local event log.